Means for utilizing tidal energy



J. O. BOVING MEANS FOR UTILIZING TIDAL ENERGY Filed Feb. 25. 1925 'NVENTOR Jzns Gflf. 30

ATTORNEY I Eye.

Patented Nov. 3, 1925.

JENS ORTEN BOVING, OF LONDON, ENGLAND.

v MEANS FOR UTILIZING- TIDAL ENERGY.

Application filed February 25, 1925. Serial No. 11,398.

To all whom it may conceive:

Be it known that I, JnNs ORTEN BOVING, subject of the King of Great Britain, residing at London, England, have invented new and useful Improvements in Means for Utilizing Tidal Energy, of which the following is a specification.

This invention relates to tidal energy utilization plants of the proposed type in which water, under the head due to difference of levels between a tidal region and a basin dammed therefrom flows down a shaft, having an inlet rising and falling with the respective water level, and ascends another shaft to escape at a lower level than the level at the inlet, and air inspired by the descending column of water separates from the water and is trapped in a chamber at the bottom of the shafts and is thus subjected to the pressure head of the colmun of water in the upcast shaft.

Now if the difference of level at the various states of tide constitutes a considerable proportion of the total hydraulic column on which'the air pressure depends, such airpressure, in the absence of special precautions to the contrary, will vary considerably with the changes in the water levels. The object of the present invention is to enable the air pressure generated'by a tidal energy utilization plant of the above described type, to be kept practically constant during all active stages of the tide.

Moreover, within the limits of the various possible maximum outputs, the means em-- ployed for this purpose also maintains the I air pressure practically constant under all changes in the various factors upon which the air pressure depends, such as variation in the difference of the levels on -the two sides of the dam, and changes in the load.

For the above purpose, according to the invention, means responsive to changes in the air pressure are provided whereby the difference between the water level above theupcast shaft andthe water level in the air-' trapping chamber is kept and remains approximately constantw For instance, as the water level above the upcast shaft varies, the water level in the air-trapping chamber is correspondingly varied by being either depressed by the compression of increased volumes of air or permitted to rise by compression of decreased volumes of air, so that the head on which the air pressure depends remains practically constant. i

This can be effected by progressively opening the intake as the pressure-effecting water level descends, the thereby increased flow of water entraining correspondingly increased quantities of air, or vice versa.

The progressive opening of the intake can be automatically controlled by a pneumatic piston or other organ the position of which isdependent upon the pressure of the air in the air-trapping chamber from which it is supplied with compressed air. a

The progressive increase in the opening of the inlet may and preferably does, as above mentioned, also compensate for the fluctuating difference between the levels of the water on the two sides of the dam; thus the output of an air turbine or other machine utilizing the compressed air can be maintained practically constant over a very wide range of fluctuating heads of-water.

A diagrammatic representation of atidal energy utilization plant arranged to maintain a constant pressure of compressed air at various stages of the tide is shown, by way of example, on the accompanying drawing, in which Fig. 1 is a transverse section through the dam, and

Fig. 2 shows a modification.

a is a dammed-in basin and b a tidalregion, between which there is an alternating interchange of water. lVith the levels in a and 6 shown on the drawing the water flows from the basin a down a telescoping pipe 0 and the fixed concrete continuation shaft thereof and up a telescoping pipe 0 into the tidal region 6.

The water flowing down the downcast pipe 0 inspires air through pipes d in a floating head 6 The so-entrained air is trapped in a chamber f beneath the dam and is subject to the pressure of the head of water in theupcast pipe 0 and tidal region 6.

g is a pipe supplying compressed air from the chamber fto turbo-generators h for ex ample. The flow of waterdown the .pipe 0 de pends upon the difference between'the levels in the basin and in the tidal region I) an'don the degree of opening of the mouth of the downcast pipe 0 This degree of opening is controlled by the degree of ap-- proach of the mouth of the telescoping pipe- 0 toits floating heade Now as the level in the tidal region 1) changes, if the level i-of the'water in the ir-trapping the pressure subjected would vary;- However,-to-- avoid variation of this pressure head Z) i it is arranged that the water level in the air trapping chamber 7 shall vary, correspondingly to the change-in the water level in the tidal region 6, whilst the water is flowing from the basin a.

To effect this maintenance of a constant difference of level Z) i, in the arrangement ilustrated a pipe j supplies compressed air from the chamber f to control a servo-motor, consisting of a cylinder is in which moves a piston Z connected by acable tackle m to the telescoping downcast pipe A distributing valve a connected to, a spring loaded piston 0 controls the supply of oil under pressure from a pipe to either end of the cylinder k. The piston 0 is so spring loaded that on decrease of air pressure in the chamber the valve is is displaced to admit oil to the righthand end'of the cyl inder k so that'its piston Z moves in a direction to lower the telescopingdowncast pipe 0 This results inincreasing the separation between the floating head 6 and the mouth of the pipe c More water consequently'flows down the pipe 0' andthe increased amount of air thus inspired and trapped depresses the level i of the water in the chamber f and thus compensates for sinking of the level in the tidal region I), keeping the pressure head Z1 2' constant.

Conversely on'increase of'the air pressure in the chamber f, the piston 0 overcomes the influence of its'spring'anddisplaces the valve' n to admit oil'to the'left handend of the cylinder 70 to move its piston Z in the direction to raise the dovvnc'ast pipe 0 This reduces the distance between the mouth of this pipe o and its floating head a and consequently reduces the infi ow of water and entrained air.

The weight of the pipe .0 is balanced'by' connecting the pipe- 0 through-thepiston Z to-the upcast'telescoping'pipe c by the cable tackle m p The mouth of the upcast pipe 0 is arranged to be suliiciently remote from its floating head 6 to allow free discharge of the operating'water, as shownin'connection' with the pipec and the floating head' 6 On reversal of the tide and consequent reversal of the flow which will then occur down the pipe 0 and up the pipe 0 the servo-motor ]cmust operate in the reverse vdirections to those above described, on increase and decrease of pressure respectively.

To permit of this, a cock 9 in the airp1pe' 7' leading to the piston 0 is cl0sed,-an'd a cook 9 in the pipej leading to a second spring loaded piston 0 is opened.- This piston o is also connected to the distributing valve a, but is oppositely spring loaded to the piston o yand thus under increases and decreases in the air pressure causes the admission of oil to the ends of the cylinder 70 the reverse to those' atwhich under like conditions the piston 0 would have caused admission.

It is obvious'th-a-t should the output and consequently the consumption of compressed air by the turbo-generators 72 vary, the servo-motor it will move the pipe 0 ando correspondingly to maintain a constant air pressure. Also variation in the operating head between the basin o and tidal region 6 is compensated for 'by this means; I

Fin. 2 shows an electrical arrangement-for operating the cables 172 m to raise and lower the pipes 0 0 Com-pressed air is supplied by a'pipey' from the air-trappingchamber to a spri lo'adcd piston o. This piston 0 is connected'to aswitch lever '1 arranged. alternatively to close a shunt; circuit 8 ,8 from electric mains 26, I? either through a solenoid al or througha solenoid a In accordance with which *solenoid u or 10- is thus energized, a core 4') is displaced in one of two opposite directions and, being connected to a reversingswitch 20, controls the rotation in one direction or the other of the armature of an electromotor a, which thereby by the cables 972 m either raisesor lowers the pipe 0 whilst lowering or raising the pipe 0 It ill be understood thatthe electric connections are" so arrangedthat on the pressureof the air acting; on the piston 0 increasing and thereby the shunt circuit 8, 8 being closed through the solenoid thus drawing: the core o to the left; the reversing switch 10 so connects the motor :0 that it winds up the downrast pipe 0 ,:t'o constrict the inlet and reduce the amount of air in-- spired.

A han d-adjusted reversing switch- 3 is provided to reverse the motor connections when on reversal of flow the pipe 0 becomes the downcast pipe. i

e isa junction'box housingthe junctions of the motor and switch leads.

1; In a tidal energy utilizationplant a downcastshaft a rising and falling inlet to said downcast shaft, means entraining air by water flowing down said inlet,-an air-trappingchamber leading from said downcast shaft, an upcast shaft leading from said air-trapping chamber, and means responsive to changes in the air pressure in said air-trapping chamber'maintaining approximately constant the difference between the Water level in said air-trapping chamber and the water level above said upcast shaft.

2. In a tidal energy utilization plant, a doWn'cast shaft, a rising and falling'inlet' to said downcast' shaft, means entrainingf air by Water flowing down said inlet, an airtrapping chamber leading from said downcast shaft, an upcast shaft leading from said airtrapping chamber, and means varying the Water level in said air-trapping chamber in correspondence With changes in the Water level above said upcast shaft.

3. In a tidal energy utilization plant, a doWncast shaft, a rising and falling inlet to said downcast shaft, means entraining air by Water flowing down said inlet, an air-trapping chamber leading from said downcast shaft, an upcast shaft leading from said air-trapping chamber, and a servo-motor controlled by the air pressure in said air-trapping chamber and increasing the opening of said inlet on decrease of said air pressure and decreasing said opening on increase of said air pressure.

4. In a tidal energy utilization plant, a downcast shaft, a floating inlet head above said downcast shaft, a downcast pipe telescoping in said downcast shaft below said floating inlet head, means entraining air beneath said floating inlet head by water flowing down said downcast pipe, an airtrapping chamber leading from said downcast shaft, an upcast shaft leading from said air-trapping chamber, a servo-motor controlled by the air'pressure in said airtrapping chamber, and suspension means interconnecting said telescoping downcast pipe and said servo-motor and displaced in alternative directions by said servomotor.

5. In a tidal energy utilization plant, a pair of shafts, a floating head above each said shaft, a pipe telescoping in each said shaft below each said floating head, means entraining air beneath said floating heads by water flowing down either said shafts, an air-trapping chamber interconnecting said shafts, a servo-motor controlled by the air pressure in said air-trapping chamber, suspension means interconnecting said telescoping pipes through and displaced in alternative directions by said servo-motor, and means for reversing the action of said air-pressure on said servo-motor on reversal of the fiowof Water through said shafts.

In testimony whereof I have signed my name to this specification.

J ENS ORTEN BOVING. 

